Lim et al. (2017) reported that a fraction of SCLCs express high levels of Hes1, indicating that Notch is activated in this SCLC subtype. This Notch-active population – called non-neuroendocrine (NE) SCLC – expresses lower levels of neuroendocrine markers. Endogenous Notch activation switches NE SCLC to the non-NE type through the expression of Rest, a transcription repressor; this means that levels of Notch activation may reflect the heterogeneity of SCLC cells. The gene discussed is HES1; the disease is small cell lung carcinoma.